add license, remove duplicate trove classifier
add license, remove duplicate trove classifier

mtsgrd/PynamoDB2,Evzdrop/PynamoDB,Villoid/PynamoDB,pynamodb/PynamoDB,joshowen/PynamoDB,jlafon/PynamoDB,mpresh/PynamoDB,khwilson/PynamoDB,borgstrom/PynamoDB,mpresh/PynamoDB